The invention relates to an integrated circuit and to a method for controlling a power supply for such an integrated circuit.
Present-day microelectronic circuits use voltage generators on chip in order to generate a stable, defined voltage from the external supply voltage. Although the external supply voltage is predetermined, it can fluctuate within the specification limits.
A typical example is the generation of an internal voltage of 2.0 V from an external supply voltage of 2.5±0.2 V. For this purpose, a plurality of voltage generators are distributed over the chip. In this case, each of the plurality of voltage generators usually comprises a pFET or nFET transistor (pull-up transistor) and a comparator. The comparator is connected via an input to a stable reference voltage, which is generally generated by a bandgap reference circuit.
Particularly in the event of small differences between the supply voltage and the internal voltage, the problem arises, however, that the number of voltage generators used on the chip has to become very large. Since these voltage generators themselves require an operating current that is not small, a significant increase in the total operating current may thus result. At the present time, the number of voltage generators is chosen such that the internal voltage can still be generated even at the lowest permissible supply voltage. Moreover, for safeguarding purposes, further generators over and above this are also included in the design.